The current CPU cores are Zen 2 which has become a massive problem the longer the generation goes. Zen 4c/5c are definitely an obvious path forward on the x86 side of things as they're faster, more efficient and have great density. It's also possible that AMD could do a shared V-Cache for an APU which would cover both CPU and GPU. I'm not sure whether or not that would end up being cheaper/more efficient than a wider memory bus though.
The only chance of Intel getting back into the console game would be if they were doing all of the manufacturing and I'm not sure there's a timeline which would work.
Arm is certainly a possibility, but you run into a graphics IP problem pretty rapidly. I'm not sure AMD, nvidia or Intel would license their IP if they didn't get something else out of it.
I don't think they'd get away without a pretty large performance improvement if they're making a new flagship no matter what way they go. HBM is a non-starter due to packaging cost even without AI. Naming wise I've gotta agree because they have had the dumbest names ever after the first one.
I'm not convinced Zen 2 is the bottleneck for console games right now, and people don't seem too excited about graphics at the moment.
V cache, maybe could be a good reason to stick with AMD, and AMD would be likely if Microsoft wants to wait a couple more years and have a repeat of this generation, presumably with even bigger-er, more power consuming, and more expensive-er consoles.
But Microsoft shouldn't want to do that. For one thing, any money Microsoft puts into making a better semi-custom AMD apu is also going to teach AMD to make a better APU for PS6. Also if Microsoft makes a console too similar to Sony, they're going to take a lot more heat when they stop making cross-platform games.
Microsoft should be realizing by now that their strategy of having the most powerful console has never come remotely close to working.
Plus, I just don't think what AMD has today will give them enough of an advantage to sell the next gen on power alone. So AMD is not the option if Microsoft wants to emulate the success of the 360 and rush to beat Sony to Market by a year or two. Granted the 360 still lost, but it was in the lead for a good while.
If the next Xbox is going to break generations, then I'm not envisioning a flagship. The Xbox series X is selling like a GameCube; Microsoft needs a Wii. Make a smaller, cheaper, "cute", colorful console that casts a wide net and brings the fun. Simplify to 1 model at launch. Ditch the current ad-first interface. They should also strongly consider letting people play online for free.
Throw in all the gimmicks. Maybe do Kinect again which will hopefully benefit a lot from AI, or anything else new they have in the works. Maybe a VR chat type thing for their avatars.
Maybe make and integrate a twitch-like platform so kids can buy jpegs with real money and run baby's first live stream with overpriced first-party accessories. Whatever it takes to look fresh. Doesn't matter.
Get it on the market first, start accumulating some wins, and holy cow get some system selling games on the thing. The "flagship" can wait a couple years and be the Pro/elite/X model - but only if absolutely necessary.